This invention relates to a separable fastener, particularly of the hook and loop type, for attachment to other objects such as polyurethane foam seat cushions or hard plastic parts for automobiles, furniture and the like. One portion of such a separable fastener is typically incorporated into the plastic object or polyurethane seating foam during a molding process for subsequent attachment to another object carrying the mating portion of the separable fastener. The fastener of this invention greatly simplifies the method of molding the part to which it is attached. Although particular reference is made herein to elastomeric polyurethane foam or hard plastic parts, it is to be understood that a fastener product according to this invention can be used in parts made from a wide variety of materials, e.g. thermoplastic materials, thermoset materials, elastomers, or any other moldable composition, and such compositions are referred to broadly as "plastics."
Hook and loop separable fasteners, such as those sold by the assignee of this invention under the trademarks "VELCRO" and "ULTRAMATE," are well known and used to join two members detachably to each other. This type of fastener has two components. Each has a flexible substrate or base having one component of the fastening system on the surface thereof. One surface typically carries resilient hooks while the other carries loops. When the two surfaces are pressed together they interlock to form a releasable engagement.
The hooks can be any of a variety of shapes, including cane-shaped hooks, palm tree-shaped hooks and mushroom-shaped hooks, all of which are well known within the art. As used within this application, the terms "hook," "hook-type" and "hook-like" shall be construed to cover any such configuration of loop-engaging element.
Separable fasteners are used in the manufacture of automobile seats in the attachment of an upholstered seat cover, hereinafter called trim cover, to a polyurethane foam bun. One portion of the separable fastener is incorporated into the surface of the polyurethane seat bun during the foam molding process. The mating portion of the separable fastener is attached to the seat cover to provide releasable attachment to the foam seat bun. The separable fastener assembly used in the foam mold for incorporation in the bun surface typically is the hooked portion of the separable fastener system. This hook portion has a base carrying resilient hooks on one surface. The surface of the base obverse of the hook-carrying surface may act as an anchoring surface by a variety of configurations well known in the art. In some assemblies a magnetically attractive material is attached to the base to facilitate placement of the assembly in a trough of the mold cavity wall, which is equipped with magnets. A protective layer, often in the form of a thin plastic film, is placed over the resilient hooks to prevent incursion of foam into the hooks during the molding process. Significant foam contamination of the hooks would affect their ability to engage with the mating portion of the fastener. Such fastening devices are applied to one surface of a clamshell mold; a chemical mixture, usually of a diisocyanate and a polyol, are injected into a mold; the upper surface of the mold is closed and clamped shut while the chemicals react and blow to form a flexible foam, well known in the art.
Prior-art assemblies, including those disclosed in U.S. Pat. Nos. 4,726,975, 4,673,542, 4,563,380 and 4,693,921 employ a thin film to prevent the incursion of foam into the fastener elements of the separable fastener during molding. French Patent 2,423,666 discloses a system for sealing the edges of the tape in the mold trough by jamming the edges of the fastener into the trough.
Two patents from which the present document claims priority disclose another arrangement for protecting the fastening elements from degradation and fouling by the foaming material. U.S. Pat. No. 5,286,431, issued on Feb. 15, 1994, to Banfield and Rocha, entitled MOLDED PRODUCT HAVING INSERT MOLD-IN FASTENER, discloses a fastener of the hook and loop type having a base member and a plurality of engaging elements upstanding from one surface thereof. An elastomeric or rubber encasement (which may be either thermoplastic or thermoset) that intimately surrounds the individual engaging elements, substantially filling all of the space around each one, protects the elements when they are exposed to the harsh environment of a molding process. The fastener is placed in a mold and molded into, as an integral part thereof, a plastic part. The encasement is removable from the engaging elements after the molding process, to expose the engaging elements, without permanently deforming or substantially destroying the fastening performance thereof. U.S. Pat. No. 5,540,970, issued on Jul. 30, 1996 to Banfield et al., entitled DIE CUT MOLD-IN, further discloses providing the elastomeric cover so that the tips of the hooks are slightly exposed. Other modifications of the invention are shown in the '970 patent as well. The disclosures of both of these patents are incorporated fully herein by reference.
All of the arrangements discussed above that entail covering the fastening elements that are to be used to attach the molded product to a trim cover or companion piece, require that the molding operation include a step to remove the protective cover, be it a film-like cover or a space filling, encasing cover. This entails a significant inconvenience for the molding operator. Further, once removed, the cover is in the possession of the molding operator, who must dispose of it. But, the molding operator is not the one who could use the cover, even if it were to be recyclable. (It is the fastener manufacturer who is in the best position to reuse the cover.) Thus, from the perspective of the molding operator, it is very beneficial to be able to use a fastening component that does not require a cover. Consequently, those whose business it is to make the fastening component to be incorporated into the molded article are interested in providing to the molding operator a component that does not have a cover that needs to be removed after molding.
It is also typically desirable to avoid any apparatus that can not be used with a conventional mold, having a simple flat bottom trench for placement of the fastening element. Otherwise, the molding operator must alter its normal equipment and way of doing business.
Thus, it is an object of the invention to provide a separable fastener component that can prevent intrusion of a molding material into the spaces between the individual engaging elements (typically hook-like elements) without requiring that a protective cover be removed after the product to which the fastener is attached, is molded. It is a further object to facilitate the manufacture of objects to which such a separable fastener component is attached, such as by molding. Another object is to provide molded articles with integral fastener components, without fouling the fastener elements of the fastener components with molding material.